John Blakeslee
Science Highlights
Figure 1.
Recapping some of the most recent and significant research
results achieved by the Gemini user community.
Gemini North GMOS color
composite image of Comet
2I/Borisov, produced from
data obtained in the g, r,
and i filters on the night of
November 11-12, 2019.
Credit: Gemini Observatory/
NSF’s National Optical-
Infrared Astronomy
Research Laboratory/AURA
JANUARY 2020
Gemini Tracks Comet 2I/Borisov from North to South
Last quarter’s GeminiFocus reported on Director’s
Discretionary Time (DDT) observations of interstellar
Comet 2I/Borisov taken with the Gemini Multi-Object
Spectrograph (GMOS) at Gemini North in early Sep-
tember 2019, not long after it was discovered. In the
ensuing months, the comet has traced a southward
arc across the sky, and Gemini has been following its
journey from both hemispheres. While diverse DDT
programs were activated to study 2I/Borisov through
October, more recent observations have been ob-
tained via Fast Turnaround (FT) proposals and a
2019B Target of Opportunity program.
In one Gemini North FT program, Rosemary Pike (Aca-
demia Sinica Institute of Astronomy and Astrophysics,
Taiwan) and colleagues used GMOS and the Near-In-
fraRed Imager and spectrometer (NIRI) to measure the optical and near-infrared (NIR) col-
ors of the dust coma and tail for comparison with Solar System comets. Team member Meg
Schwamb (Queen's University, Belfast) participated in the November observations via the
“eavesdropping” option. Although most of the observations were taken with non-sidereal
tracking, the observers also obtained a sequence of sidereally tracked exposures for pho-
tometry of reference stars. These exposures were then used to make a color composite im-
age, shown in Figure 1, that found its way into the pages of The New York Times.
January 2020 / 2019 Year in Review
GeminiFocus
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